Modeling of Electron Mobility of GaN at Low Temperature and Low Electric Field

Author(s) Souradeep Chakrabarti, Shyamasree Gupta Chatterjee, Somnath Chatterjee
Affiliations Techno India Salt Lake, EM 4/1, Salt Lake, Kolkata – 700091
Issue Volume 3, Year 2011, Number 1, Part 5
Dates Received 04 February 2011, published online 08 December 2011
Citation Souradeep Chakrabarti, Shyamasree Gupta Chatterjee, Somnath Chatterjee, J. Nano- Electron. Phys. 3 No1, 1071 (2011)
PACS Number(s) 73.61.Ey,73.50.Bk,72.10._d
Key words Modeling of electron mobility, M-B statistics, Degeneracy, Low temperature (2) , Elastic scatterings, Acoustic phonon deformation potential, Acoustic phonon piezoelectric, Ionized impurity, Dislocation scattering, Neutral impurity.
An analytical model at low temperature and low field electron mobility of GaN has been developed. The electron mobility in GaN have been calculated using Relaxation Time Approximation method considering elastic process of acoustic phonon deformation potential scattering, acoustic piezoelectric scattering and ionized impurity scattering, neutral impurity scattering, dislocation scattering. Ionized impurity scattering has been treated beyond the Born approximation using Dingle and Brooks- Herring analysis. The compensation ratio is used as a parameter with a realistic charge neutrality condition. Degeneracy is very important factor as it is used to imply different statistics (Maxwell – Boltzmann or Fermi – Dirac) at different temperature. Generalized M-B statistics are used throughout because the samples we have used to compare our results are highly Non-degenarate. The result shows that, the proposed model can accurately predict the electron mobility as a function of both the carrier concentration and the temperature upto 200 K. The discrepancy of this model above temperature 200 K presumably results from the following factors: ignoring the role of optical phonon, at low temperature consideration of parabolic band i.e. neglecting the effect of inter-velly scattering and ignoring the effect of very few interfacial charges in the degenerate layer at the GaN-substrate interface.